Download Right ventricular diastolic function in chronic obstructive lung disease

Eur Resplr J
1992, 5, 438-443
Right ventricular diastolic function in chronic
obstructive lung disease
S. Marangoni, S. Scalvini, M. Schena, M. Vitacca, A. Quadri, G. Levi
Right ventricular diastolic function in chronic obstructive lung disease. S. Marangoni,
S. Scalvini, M. Schena, M. Vitacca, A. Quadri, G. Levi.
ABSTRACT: Early detection of diastolic dysfunction in chronic obstructive
lung disease (COLD) patients could have great prognostic value. Echocardiography has been shown to be a useful technique in studying left ventricular diastolic function. A noninvasive method of studying right ventricular
diastolic function has not yet been reported.
Pulsed Doppler echocardiography was used to assess right ventricular diastolic
function in three groups of subjects: Group 1: 35 COLD patients with pulmonary hypertension; Group 11: 32 COLD patients without pulmonary hypertension; and Group Ill: 18 control subjects. Ratios between peak atrial filling
velocity (A) and peak early filling velocity (E) (A/E), deceleration half times of
the right ventricular rapid filling wave (DHT), and the Interval between
pulmonary valve closure and tricuspid valve opening (isovolumic relaxation
times) (Pc-To) were significantly different in Group I in comparison to Groups
11 and Ill. Sensitivity of A/E ratio and Pc-To were 82 and 77%, respectively,
and speclficity 90 and 72%, respectively; positive predictive values were 90 and
75%, respectively, and negative predictive value 82 and 74% respectively. The
multiple correlation coefficient between A/E, acceleration time (ACT), DHT, PcTo and mean pulmonary artery pressure was 0.75 for Groups I and ll together.
In conclusion 2D echo-Doppler proved to be useful in evaluating right ventricular diastolic function in all hypertensive COLD patients, revealing a high
correlation between diastolic parameters and mean pulmonary artery pressure
in both normotensive and hypertensive COLD patients.
Eur Respir J., 1992, 5, 438-443.
Recent studies have demonstrated that diastolic
abnormalities are one of the earliest manifestations of
cardiac dysfunction and are frequently detected more
easily than the abnormalities in systolic ventricular
performance in cardiopulmonary diseases [1, 2).
The study of left ventricular diastolic function using
a variety of techniques has revealed an impairment of
the compliance and of the ventricular relaxation in
coronary artery disease, hypertrophic cardiomyopathy,
hypertensive heart disease, aortic valve disease, congestive cardiomyopathy, and pulmonary hypertension
primary and secondary to chronic obstructive lung
disease (COLD) [3, 4). Despite growing interest in
such techniques, none has been shown to be completely accurate and the precise assessment of intrinsic right ventricular (RV) diastolic function remains
elusive [5-7). The reason for this is that diastole is
a complex sequence of interrelated events which are
not completely understood.
Among the methods still available, echo-Doppler has
been used with relative success by several investigators in the study of left ventricular diastolic dysfunction in cardiological diseases [8-12). However, fewer
Fondazione Clinica del Lavoro di Pavia
Research and Care Institute
Dept of Cardiopulmonary Rehabilitation
Gussago (BS)
Italy.
Correspondence: S. Marangoni
Clinica del Lavoro Foundation
Dept of Medical Rehabilitation
Via Pinidolo, 23
25064 Gussago (BS)
Italy.
Keywords: Chronic obstructive lung
disease
pulmonary hypertension
pulsed Doppler echocardiography
right ventricular diastolic dysfunction.
Received: October 27, 1990
Accepted after revision October 22,
1991.
studies have been conducted on right ventricular
diastolic dysfunction which is especially associated
with cardiopulmonary diseases [13).
The present study was undertaken to investigate the
usefulness of Doppler echocardiography in determining right ventricular diastolic function in three groups
of subjects: one group with COLD and pulmonary hypertension, one group with COLD without pulmonary
hypertension, and a control group.
Patients and methods
Patients
The study sample considered 67 COLD patients who
needed a right heart catheterization. An echo-Doppler
was systematically performed. A mean pulmonary
artery pressure of :s:20 mmHg was considered normal.
The patients were divided in two groups:
Group 1: 35 patients, 33 males, 2 females, mean age
62:t9 yrs (30-79 yrs), with COLD and pulmonary
hypertension, mean pulmonary artery pressure (mPAP)
27.5:t6.1 mmHg, (20-45 mmHg).
RIGHT VENTRICLE DIASTOLIC ASSESSMENT, ECHO DOPPLER
Group 11: 32 patients, 29 males, 3 females, mean age
58±12 yrs (21-76 yrs), with COLD and without
pulmonary hypertension, mPAP 14.3±4.6 mmHg
(4-19 mmHg).
Nine patients from Group I and four patients from
Group 11 were excluded because their recordings were
not satisfactory. In these patients it was difficult to
obtain the tricuspid flow velocities with a good spectral envelope. The rate of success of Doppler examination in Group I was 78% and in Group 11 was 88%.
Group Ill: a control group of 18 normal subjects, all
males, mean age 53±13 yrs (32-78 yrs), who were
asymptomatic and showed no evidence of cardiovascular or pulmonary disease as confirmed by physical
examinations.
At the time of the study, Group I and 11 patients
were being treated with inhaled beta 2 -agonist
bronchodilators and theophylline. Some patients were
also being treated with diuretics. No patient was
undergoing domiciliary oxygen therapy. All patients
(in Groups I and 11) were in a stable clinical condition and sinus rhythm. The patients with clinical evidence of hypertensive, ischaemic, valvular (in
particular severe tricuspid or pulmonary regurgitation)
heart disease and neuromuscular disease were excluded
from the study.
Informed consent was obtained from each subject
studied.
Methods
All subjects underwent spirometric (Werner Gut Diffusion-Star FG 90) and haemogasanalytic (ABL 330
Radiometer) tests. M-Mode and two-dimensional
echocardiograms and pulsed Doppler were performed
with a Toshiba SSH40 scanner using a 2.5 MHz transducer. All subjects were examined in a supine position from a subcostal approach with the short axis
view at the aortic valve level in order to see the RV
outflow tract and the pulmonary valve leaflets.
The transducer was also positioned at the cardiac
apex to obtain a four chamber view, whilst maintaining the Doppler beam as parallel as possible to the
long axis of the RV inflow tract. In order to measure the tricuspid inflow velocity, the Doppler sample
volume was placed in the right ventricle near the tricuspid orifice. The measurements were carried out at
end-expiration. The tracing was recorded on a stripchart simultaneously with an electrocardiogram at a
paper speed of 50 mm·s· 1• Examinations were performed by a single examiner. Measurements were
taken of the RV end-diastolic diameter (RVED) and
the right atrium (RA) end-systolic diameter and RA
area calculated by means of a computerized trace by
the echocardiogram.
The isovolumic relaxation time, the interval from the
pulmonary valve closing to the tricuspid valve opening (Pc-To interval), was also calculated. This time is
the difference between the interval from the Q wave
on the electrocardiogram (ECG) to the onset of
439
diastolic tricuspid flow and the interval from the Q
wave on the ECG to the end of systolic pulmonary
flow. The Doppler recordings of trans-tricuspid flow
from the cardiac apex have a characteristic biphasic
appearance. Two distinct peaks representing early
diastolic, or "passive" filling, velocities (Evel) and late
diastolic, or atrial velocities (Avel) were clearly identified and measured along with their ratio (A/E).
Acceleration time (ACT) (the interval between the beginning and the peak of the E wave) and deceleration
half time (DH1) of early diastolic rapid filling were
also measured. All measurements were obtained by
averaging the values of five consecutive tricuspid and
pulmonary flow velocities. In all subjects, the 2D
echo-Doppler was performed one or two days before
right heart catheterization.
All patients remained unsedated while undergoing
right heart catheterization with a floating catheter
(Grandjean) to evaluate pulmonary artery, right ventricle, and right atrium pressures.
Statistical analysis
The data were expressed as means and standard deviations. A multivariate analysis of variance of the
nine echocardiographic variables between the three
groups was performed . .Moreover, the comparisons of
Group 11 versus Group Ill and between Groups 11 plus
Ill versus Group I were made. The same scheme of
analysis was carried out on each of the nine
echocardiographic data (14].
Multiple and single regression analyses were used to
evaluate the relationships between the diastolic parameters and mean pulmonary artery pressure (mP AP).
For each echo- Doppler parameter sensitivity,
positivity, positive and negative predictive values in
detecting patients with pulmonary hypertension were
calculated [15].
Results
Group means of the functio:~.al respiratory,
haemogasanalytic, and haemodynamic parameters are
shown in table 1. Tables 2 and 3 show the echoDoppler RV systolic and diastolic parameters.
The multivariate analysis of echo-Doppler variables
between the three groups proved highly significant
(F=8.80 with 18 and 150 degrees of freedom (d.o.f.),
p<0.0001). The comparison of Group 11 versus Group
Ill had low significant difference (F=2.59 with 9 and
75 d.o.f., p=0.05), whereas the comparison of these
two groups versus Groups I had high significant difference (F=21.62 with 9 and 75 d.o.f., p<0.00001).
The analysis of the single echocardiographic variables showed a similar result for the global test; in the
test performed between Group 11 and Ill peak early
diastolic filling velocity (Evel), ratio between peak
atrial filling velocity (A) and peak early filling velocity (E) (NE), acceleration time and isovolumic relaxation time did not prove significant.
S. MARANGONI ET AL.
440
Table 1.
data
-
Clinical, respiratory and haemodynamic
Groups
Age
Sex
HR
VC
FEV1
FEVINC
Po 2
Pco2
PAP syst
PAP diast
mPAP
RVP syst
RVP diast
RAP syst
RAP diast
mRAP
yrs
M!F
b·min·1
l
J.s·l
%
kPa
kPa
mmHg
mmHg
mmHg
mmHg
mmHg
mmHg
mmHg
mmHg
I
II
Ill
n=35
n=32
n=18
62:t9
16/19
73.1:t12.3
2.12:t0.72
0.93:t0.52
42.9:t14.0
7.2:t1.4
6.4:tl.l
41.2:t9.0
17.4:t7.8
27.5:t6.1
46.0:t5.6
4.7:t3.0
6.5:t2.6
2.5:t1.8
4.0:t2.2
58:t12
18!14
68.1:t9.9
2.91:tl.06
1.37:t0.83
44.5:t16.5
9.6:t1.7
5.3:t8.80
23.5:t6.8
9.0:t4.8
14.3:t4.6
24.0:t4.5
3.9:t2.0
5.6:t2.5
1.6:tl.l
3.4:t2.2
53:t13
14/4
67.8:t14.1
3.64:t0.98
3.03:t0.84
88.0:t14.0
11.5:tl.l
4.6:t0.1
time of the tricuspid inflow velocities were in the
normal range in the control Group and in normotensive patients and changed significantly in hypertensive
patients. The ACT of the tricuspid inflow velocity did
not change in the analysis made between Group I and
Group 11 but it was significantly different between
Group I and Group Ill. The right ventricle enddiastolic diameter (sensitivity: 94%, specificity: 81%,
positive predictive value: 84% and negative: 93% ),
right atrium diameter and right atrium area were significantly greater in Group I in comparison to subjects
from Group 11 and Group Ill (table 4).
Table 3. -
Groups
Diastolic
parameters
Right ventricular systolic parameters
Groups
NS
0.93±0.27
Avel ms
0.92:t0.23
0.67±0.15
NS
0.73:t0.16
NE
1.27:t0.31
0.82±0.22
NS
0.90:t0.18
104.7:t21.4
79.3:t20.4
NS
0.83:t19.2
ACT ms
II
III
n=32
n=18
RPEP ms
129:t27
...
116:t21
NS
110:t18
RVET ms
281:t32
••
304±38
NS
306±27
NS
0.38±0.08
0
00
0.30:t0.08
000
ACT ms
ACT/RVET
n=18
0.75:t0.20 NS 0.84±0.17
93:t15
000
140:t30
NS
154±19
0.33±0.07
000
0.45±0.08
NS
0.50:t0.05
RPEP: right pre-ejection period; RVET: right ventricular
ejection time; ACT: acceleration time; Ns: nonsignificant.
*: p<0.05; **: p<0.01; 0 : p<0.005; oo: p<0.001; ooo:
p<O.OOOl. Mean±so.
Table 4 shows the sensitivity, specificity, positive
and negative predictive values of the echo-Doppler
indices analysed for the diagnosis of pulmonary hypertension.
The mean value of peak late diastolic or atrial filling velocity (Avel) and (NE) ratio were significantly
different in Group I patients from those of Groups 11
and Ill. The sensitivity of the NE ratio in detecting
patients with pulmonary hypertension was 82%, the
specificity was 90%, the positive predictive value was
90% and negative 82%.
Mean isovolumic relaxation time (sensitivity 77%,
specificity 72%, positive predictive value 75%, negative predictive value 74%) and mean deceleration half
00
30.4±5.5
•••
00
••
•
97.5:t14.5 NS 106.7:t28.4
NS 115.8:t35.6
00
Pc-To ms
0.46±0.12
n=32
27.1:t4.1
DHT ms
RPEP/RVET
III
NS
Table 2. -
••
II
00
38.0:t8.7
Evel ms
n=35
n=35
RVED mm
HR: heart rate; VC: vital capacity; FEV1: forced expiratory
volume in one second; FEV1NC: forced expiratory volume
at first second on vital capacity; PAP: pulmonary arterial
pressure; diast: diastolic; syst: systolic; RVP: right ventricular pressure; RAP: right atrial pressure; ~o1 : oxygen tension;
Pco 2: carbon dioxide tension; m: mean. Mean:tso.
Systolic
parameters
RV diastolic and cardiac parameters
65.0:t20.8
00
32.6:t23.8
NS
34.1:t25.0
RV: right ventricle; RVED: right ventricle end-diastolic diameter; Evel: peak early diastolic filling velocity; Avel: peak
late diastolic or atrial filling velocity; AlE: ratio between
peak atrial filling velocity (A) and peak early filling velocity (E); DHT: deceleration half time; ACT: acceleration time;
Pc-To: the interval between the pulmonary valve closure (Pc)
and the tricuspid valve opening (To) (isovolumic relaxation
time). *: p<0.05; **: p<0.01; 0 : p<0.001; oo: p<O.OOOl.
Mean:tso.
For combined Group I and 11 values, simple correlation coefficients between the A/E ratio and the
atrium diameter and area were. 0.65 (p<0.0001) and
0.57 (p<0.001), respectively. Significant simple correlations were also found between DHT and right
atrium diameter r:0.57 (p<0.001), and between DHT
and right atrium area r:0.47 (p<0.005). The simple correlation coefficients between mean pulmonary artery
pressure and Avel, NE ratio (fig. 1), deceleration time,
and isovolumic relaxation time were 0.45 (p<0.005),
0.63 (p<0.0001), 0.51 (p<0.0005), and 0.62
(p<0.0005), respectively. The other parameters showed
nonsignificant correlations with mean pulmonary artery
pressure. Figure 2 shows the multiple correlation
coefficient between isovolumic relaxation time, A/E
ratio, acceleration and deceleration half times (mPAP
predicted by these values) and mPAP (observed by
right heart catheterization) was 0.75 (p<0.0001). The
multiple regression equation was mPAP=3.22:t8.49,
NE:t0.10, Pc-To- 0.034, ACT+ 0.080 DHT.
RIGHT VENTRICLE DIASTOLIC ASSESSMENT, ECHO DOPPLER
441
Table 4. - Sensitivity, specificity, positive and negative predictive values of echo-Doppler
parameters (cut-off values for tests positivity)
Sensitivity
Specificity
Positive predictive value
Negative predictive value
RVED
>26 mm
Eve!
>90 ms
Avel
>70 ms
AlE
>1
DHT
>80 ms
ACT
<110 ms
Pc-To
>50 ms
94
81
84
92
82
43
61
70
85
45
62
75
82
90
90
82
34
18
31
20
11
40
17
29
77
71
75
74
For abbreviations see legend to table 3.
w
1.4
~
1.1
0.8
mPAP mmHg
Fig. 1. - Correlation between AlE ratio and mean pulmonary
artery pressure. Note that when AlE value >1.0 all mPAP are >19
mmHg. Some hypertensive patients present AlE valves below 1.0
A/E: ratio between peak atrial filling (A) and peak early filling
(E) velocities. mPAP: mean pulmonary artery pressure.
~
Q)
(/)
.c
0
10
50
Predicted
Fig. 2. - Correlation between mPAP predicted by AlE ratio, PcTo, deceleration time, acceleration time, and mPAP observed by
right heart catheterization (see text for details). Pc-To: interval between pulmonary valve closure and tricuspid valve opening
(isovolumic relaxation time). For further abbreviations see legend
to figure 1.
Discussion
Three factors comprise the ventricular diastolic
function: the muscle stiffness that represents the resistance to myocardial stretching, the ventricular relaxation and the chamber stiffness defined as a change in
pressure relative to a change in chamber volume. The
opposite to this relationship is chamber compliance.
The clinical phases of diastole are: a) the isovolumic
relaxation time; b) the rapid filling phase; c) the slow
filling phase; and d) the atrial contraction. Studies of
left ventricular (LV) diastolic function and Doppler
mitral inflow parameters have demonstrated that the
isovolumic relaxation time depends not only on the
rate of relaxation but also on the aortic pressure and
left atrial pressure. The E wave velocity, point b, is
affected not only by the rate of relaxation, but also
by the left atrial and pre-load pressure and the presence of mitral regurgitation [6]. It was also reported
that atrial contraction velocity (Avel) is affected by
age [7], heart rate, rate of early filling, and atrioventricular interval [8].
These abnormalities in diastolic function have been
shown in noninvasive studies of patients with coronary
artery disease [9], hypertrophic cardiomyopathy [10],
and systemic hypertension [11 ]. Left and right ventricular dysfunction has been reported in dilated
cardiomyopathy [12]. It thus appears that the determining rule for calculating the isovolumic relaxation
time, early and late diastolic peak flow velocities and
early diastolic deceleration half-time is important to
understand the interrelation between diastolic and
systolic function, especially in cardiopulmonary patients [13].
In COLD patients with cor pulmonale several echocardiographic approaches are used to evahiate PAP.
The M-Mode and two-dimensional echocardiography
are useful to evaluate the RV wall hypertrophy and
RV dilatation associated with pulmonary hypertension
[16, 17]. In the past the pulmonary valve morphology was also correlated with PAP [18]. Unfortunately,
these methods had low correlation with PAP.
Some authors have used pulsed Doppler ultrasound
to measure the isovolumic relaxation time [19] and
right ventricular systolic time intervals [20] and flow
velocity in the pulmonary artery or in the RV outflow
tract. In these studies, the alteration in acceleration
time (AT), in the AT/RV ejection time ratio showed
the best correlation with PAP [21, 22] . Continuous
Doppler ultrasound techniques are used to measure the
tricuspid flow velocity when tricuspid valve insufficiency is present [23]. In this case, the systolic pressure gradient between the RV and right atrium is
measured by calculating the maximum leak velocity by
means of the Bernouilli equation. The RV systolic
pressure or systolic pulmonary artery pressure is measured by adding to this gradient the right atrial
pressure obtained clinically.
442
S. MARANGONI ET AL.
In COLD patients with pulmonary hypertension,
abnormalities of the inferior vena caval flow suggesting RV compliance impairment have been reported
[24]. RV radionuclide angiography in COLD patients
with pulmonary hypertension has been reported to
show a decrease in the right atrial early diastolic emptying rate suggesting an alteration in RV compliance
[25]. In the present echocardiographic study COLD
patients with medium or severe tricuspid regurgitation
are excluded and RV filling parameters are used to
assess diastolic function. The patients with pulmonary
hypertension revealed lower E velocities and higher A
velocities. This suggests that an AJE ratio >1, as this
has high sensitivity, specificity, positive and negative
predictive values, is the best index to discriminate hypertensive from normotensive COLD patients as well
as from control subject.
All of the patients with COLD and low pulmonary
artery pressure had a normal right atrial pressure. The
normality of the right atrial pressure excluded the presence of the diastolic dysfunction with a normal AJE
ratio, according to the concept of normalized or
hypernormal ratio with a increased atrial pressure demonstrated by several authors in the left ventricle. Hypertensive patients showed a lengthening of the
isovolumic relaxation time interval, due to an overload
of RV pressure and a low pressure gradient between
RA and RV. This index also shows good sensitivity,
specificity, positive and negative predictive values. The
deceleration time was increased in hypertensive COLD
patients which indicated prolonged myocardial relaxation [25]. The increase in the peak velocity of atrial
filling indicated increased atrial contribution to ventricular filling. These parameters show that RV
diastolic function was altered and was compensated by
an increase in atrial filling.
Hypertensive patients also demonstrated larger right
ventricle and right atrium diameters and areas in comparison with normotensive patients and the control
subjects. The right ventricle shows high sensitivity,
specificity, positive and negative predictive values. In
Groups I and 11 there was a significant correlation
between these right cardiac parameters and the NE
ratio and DHT. The patient parameters which showed
a high correlation directly with mPAP included AJE
ratio, deceleration half time, acceleration time and
isovolumic relaxation time, with the multiple correlation coefficient between these indices and mPAP being 0.75. The mechanisms of the impairment of RV
diastolic function in COLD patients needed further
clarification. It is probable that RV wall hypertrophy
plays an important role in the pathogenesis of RV impairment, but measurement of RV wall thickness is
difficult since it is frequently indistinct on the
echocardiogram. Also, the hypoxaemia increasing the
pulmonary arterial resistance could be important but in
our patients a large oxygen tension (Po 2) scattering
was present and this excludes the possibility of evaluating the correlation between Po and A/E.
The COLD patients with pulmonary hypertension
also showed modifications of some systolic echo-
cardiographic parameters (table 2). Therefore, in
COLD patients with cor pulmonale (Group I), a
diastolic dysfunction was found to be associated with
systolic abnormalities.
This confirms the previously reported finding that
diastole represents a complex interplay of multiple factors including RV and RA systolic and diastolic properties, sympathetic tone, and loading conditions and
that the pattern of filling may not reflect all of the
diastolic properties of the right ventricle. The implications of these data as regards the pathogenesis and
treatment of cor pulmonale require further study.
Nonetheless, the present results suggest that Doppler
echocardiography could be a useful technique in
assessing RV diastolic function.
References
1. Shub C. - Heart failure and abnormal ventricular
function. Pathophysiology and clinical correlation (Part 2).
Chest, 1989; 96: 906-914.
2. King KS, Gibson DG. - Impairment of diastolic function by shortened filling period in severe left ventricular disease. Br Heart J, 1989; 62: 246-252.
3. Gaasch WH, Levine HJ, Quinones MA, Alexander JK.
- Left ventricular compliance: mechanisms and clinical
implications. Am J Cardiol, 1976; 38: 645-653.
4. Mirsky I. - Assessment of diastolic function: suggested methods and future considerations. Circulation, 1984;
69: 836-841.
5. Stevenson JG. - Comparison of several noninvasive
methods for estimation of pulmonary artery pressure. J Am
Soc Echo, 1989; 2: 157-171.
6. Fioretti P, Brower RW, Meester GT, Serruys PW. Interaction of left ventricular relaxation and filling during
early diastole in human subjects. Am J Cardiol, 1980; 46:
197-203.
7. Miller TR, Grossman SJ, Schectman KB, Biello DR,
Ludbrook PA, Ehsani AA. - Left ventricular diastolic filling and its association with age. Am J Cardia/, 1986; 58:
531-535.
8. Masuyama T, Kodama K, Nakatani S, Kitabatake A. Effects of atrioventricular interval on left ventricular
diastolic filling assessed with pulsed Doppler echocardiography. Cardiovasc Res, 1989; 23: 1034-1042.
9. Fujii J, Yazaki Y, Sawada H, Aizawa T, Watanabe H,
Kato K. - Noninvasive assessment of left and right ventricular filling in myocardial infarction with a twodimensional Doppler echocardiographic method. JAm Coli
Cardiol, 1985; 5: 1155-1160.
10. Suwa M, Hirota Y, Kawamura K. - Improvement in
left ventricular diastolic function during intravenous and oral
diltiazem therapy in patients with hypertrophic cardiomyopathy: an echocardiographic study. Am J Cardia/, 1984; 54:
1047-1053.
11. Inouye I, Massie B, Loge D, Topic N, Silverstein D,
Simpson P, Tubau J. - Abnormal left ventricular filling:
an early finding in mild to moderate systemic hypertension.
Am J Cardiol, 1984; 53: 120-126.
12. Takenaka K, Dabestani A, Gardin JM, Russell D, Clark
S, Allfie A, Henry WL.
Pulsed Doppler
echocardiographic study of left ventricular filling in dilated
cardiomyopathy. Am J Cardiol, 1986; 58: 143-147.
13. Spirito F, Quarta CM, Bacca F, Scoditti S. - Studio
RIGHT VENTRICLE DIASTOLIC ASSESSMENT, ECHO DOPPLER
del flusso transtricuspidale con eco-Doppler nei soggetti
con broncopneumopatia cronica. Ecocardiografia, 1989; 2:
21-26.
14. Morrison DF. - In: Multivariate Statistical Methods.
McGraw Hill, 1976; pp. 3-5.
15. Can) B. - In: L'Ergometria. Carlo Erba ed., 1987;
pp. 43-44.
16. Tsuda T, Sawayama T, Kawai N, Katoh T, Nezuo S,
Kikawa K. Echocardiographic measurement of right
ventricular wall thickness in adults by anterior approach. Br
Heart J, 1980; 44: 55-61.
17. Panidis IP, Ross J, Ren JF, Kotler M, Mintz G.
Comparison of independent and derived M-Mode
echocardiographic measurements. Am J Cardiol, 1984; 54:
694-696.
18. Acquatella N, Schiller NB, Sharpe DN, Chatterjee K.
- Lack of correlation between echocardiographic pulmonary valve morphology and simultaneous pulmonary artery
pressure. Am J Cardiol, 1979; 43: 496-501.
19. Hatle L, Angelsen BAJ, Tromsdal A. - Non-invasive
estimation of pulmonary artery systolic pressure with
Doppler ultrasound. Br Heart J, 1981; 45: 157-165.
20. Torbicki A, Hawrylkiewicz I, Zielinski J. - Valve of
M-Mode echocardiography in assessing pulmonary arterial
pressure in patients with chronic lung disease. Cl Resp
Physiol, 1987; 23: 233-239.
21. Isobe M, Yazaki Y, Takaky F, Koizumi K, Hara K,
443
Tsuneyoshi H, Yamaguchi T, Machii K. - Prediction of
pulmonary arterial pressure in adults by pulsed Doppler
echocardiography. Am J Cardiol, 1986; 57: 316-321.
22. Martin-Duran R, Larman M, Trugeda A, Vazquez De
Prada JA, Ruano J, Torres A, Figueroa A, Pajaron A, Nistal
F. - Comparison of Doppler-determined elevated pulmonary arterial pressure with pressure measured at cardiac
catheterization. Am J Cardiol, 1986; 57: 859-863.
23. Yock PG, Popp RL. - Noninvasive estimation of
right ventricular systolic pressure by Doppler ultrasound in
patients with tricuspid regurgitation. Circulation, 1984; 70:
657-662.
24. Gary SM, Morris NK, Wayne RP, Abdulmassih
SI, Sally AK.
Real-time inferior vena caval ultrasonography: normal and abnormal findings and its use in
assessing right-heart function. Circulation, 1981; 64: 10181025.
25. Berger HJ, Matthay RA, Loke J, Marshall RC,
Gottschalk A, Zaret BL. - Assessment of cardiac performance with quantitative radionuclide angiography: right ventricular ejection fraction with reference to findings in
chronic obstructive pulmonary disease. Am J Cardiol, 1978;
41: 897-905.
26. Nishimura RA, Abel MD, Hatle LK, Tajik AJ. - Assessment of diastolic function of the heart: background and
current applications of Doppler echocardiography. Part 11.
Clinical Studies. Mayo Clin Proc, 1989; 64: 184-201.